The former Lucky Jim mine is located immediately southwest of Bear Lake and the historic mining community of Zincton.
The area is underlain by northwest striking and southwestward dipping Triassic Slocan Group sedimentary and metasedimentary rocks. The fissile lower portion of this group was historically referred to as the "slate belt" but includes limestone, calcareous argillites and quartzite beds. In the vicinity of the former Lucky Jim mine this unit is referred to as the Zincton member of the Slocan Group. Several relatively thin granitic sills and dikes intrude this strata.
The Lucky Jim mine is within a package of thinly bedded, slaty, calcareous argillite and quartzite as well as several distinct bands of limestone. The sediments strike 320 degrees and dip 40 to 80 degrees southwest. The hostrock limestone, within the former Lucky Jim mine area, is part of a major west-northwest plunging crossfractured fold structure. Brecciation, especially evident in the limestone, suggests that considerable differential movement has occurred.
Where undeformed, the "Lucky Jim" limestone has an average thickness of approximately 9 metres and a horizontal width of 6 to 61 metres. It has a faintly banded to massive appearance, a finely crystalline texture, and dark grey to black colour. Where strongly deformed, as it is throughout the productive section of the mine, it has been significantly thickened by folding. As a result, most of the limestone has been brecciated and, locally fractured.
The general structure controlling the Lucky Jim mineralization is the west-northwest plunging fold complex which can be traced from the highest to lowest levels of the mine. On successive cross- sections, the "mine fold" varies considerably in size and outline. Within the upper, southeasterly parts of the mine, it is essentially an irregular dragfolded, buckled and thickened interval of the limestone bed with a general southwesterly dip of approximately 40 degrees. Within the lower, northwesterly workings, it is a wide, complexly folded, pinching and swelling mass of limestone relating to a broad, flat wrap in the generally southwesterly dipping section. The resulting deformation has produced a characteristic breccia structure, with thicknesses ranging from 15 to 45 metres or more.
The most apparent structural controls of the ore mineralization are: (a) vertical crossfractures, or crossfracture zones striking at approximately 090 degrees (right angles) to the average regional strike of the bedding and are themselves mineralized to varying degrees; (b) plunging fold or buckle axes, with the replacement mineralization occurring as streaks, masses and disseminations within the limestone (breccia); (c) vertical longitudinal fractures, or zones of fracturing roughly parallel to the general strike of the limestone within the lower mine workings and (d) combinations of the above noted controls. Pervasive replacements on zones or crossfractures are produced near vertical tabular orebodies with widths of up to 12 metres, and lengths related to the local widths of limestone traversed by the crossfractures. Vertical longitudinal fractures are apparently less important as ore controls than (a) and (b). These probably account for the bulk of the mineralization below the No. 5 level.
The orebodies at the Lucky Jim mine are the result chiefly of replacement of limestone. Mineralization predominantly consists of sphalerite, pyrite, calcite and very minor quartz in a limestone (calcite) gangue. The relative proportion of pyrite and sphalerite varies considerably, and some mineralization is composed dominantly of pyrite. The ore in any body occurs as pods, lenses, stringers and irregular masses, locally forming a systematic pattern but more often not. The boundaries of an orebody are commonly distinct, with very little gradation from ore through low-grade material, into barren rock. Small, isolated patches of mineralization are rare. Galena is common in the crossfracture zones of the upper levels (above No. 5 level), but has not been a recoverable constituent of the ore below the No. 5 level. Tin occurs as minute amounts within the sphalerite and partly in the form of cassiterite. Other minerals include pyrrhotite and, locally, very minor arsenopyrite.
Three important fracture zones have been explored and developed at the former Lucky Jim mine, each hosting significant orebodies. From northwest to southeast these are the Glory Hole fracture zone, the Central or Main fracture zone and the Big or New fracture zone. The zones are 38 to 53 metres wide and 84 to 91 metres apart. In the Glory Hole and Central or Main fractures, ore was hosted in irregular, chimney-shaped ore shoots, up to 15 metres diameter, in limestone on either side of the fissure or within narrow zones of closely-spaced fractures or fissures. Four important and distinct fracture zones were discovered and mined in the Central or Main zone, which was 46 metres wide. In the Big fracture zone, mineralization was hosted in replacement bodies developed along strike of the limestone. The largest mineralized zone of this mine, the Larson stope, extends from 61 metres above the No. 3 level to the No. 4 level, maintaining an average width of 3 metres over 46 metres length. The zone contained considerable high grade lead ore.
The Lucky Jim mine is developed by six adits at elevations ranging from 1083 metres at the portal of the No. 9 level (haulage level) to 1420 metres at the No. 1 level. The orebodies have been mined through a vertical range of approximately 365 metres. Most of the development work has been, and most of the production has come from above No. 5 level at the 1220 metre elevation. Early operations were confined to the Glory Hole and Central fracture zones while after 1926 most was from the Big fracture zone. Production from the Lucky Jim mine began with the first shipment of ore in 1893 and continued intermittently until 1959. Total recorded production amounts to 1,065,798 tonnes with 18,634,368 grams silver, 2799 grams gold, 194,847 kilograms cadmium, 3,697,184 kilograms lead and 79,798,689 kilograms zinc recovered.
Interest in the former Lucky Jim mine since 1959 has been expressed by exploration by Swim Lake Mines Ltd. in 1971, J. Bell in 1983 and J. Ross in 1987. No further underground development or production was done. A rock sample taken near the upper adit on the St. George claim in 1983, under option to Nomad Energy and Resources Ltd., yielded 32.8 per cent zinc, 66.17 grams per tonne silver, 0.49 per cent lead and 0.18 per cent cadmium (Assessment Report 12249). The sample, ZR-003, was a 50-centimetre chip sample across a fracture zone in limestone containing sphalerite, pyrite and galena in a gangue of calcite and ankerite.
